High zinc aluminum alloy products

ABSTRACT

The present invention, in an embodiment, is cast product in the form of an aluminum alloy strip. The aluminum alloy strip includes 4 wt. % to 28 wt. % zinc and a variation of a weight percent of the zinc is 15% or less between a surface and a thickness center of the aluminum alloy strip.

RELATED APPLICATION

This application claims the priority of U.S. provisional applicationSer. No. U.S. Ser. No. 62/437,489, entitled “High Zinc Aluminum AlloyProducts” filed Dec. 21, 2016, which is incorporated herein by referencein its entirety for all purposes.

BACKGROUND OF INVENTION

Casting aluminum alloys to form cast aluminum alloy products is known.

TECHNICAL FIELD

The present invention relates to cast aluminum alloy products, andproducts derived therefrom.

BRIEF SUMMARY OF INVENTION

In one or more embodiments detailed herein, the present invention is acast product comprising an aluminum alloy strip; wherein the aluminumalloy strip comprises: 4 wt. % to 28 wt. % zinc; and wherein a variationof a weight percent of the zinc is 15% or less between a surface and athickness center of the aluminum alloy strip.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 6 wt. % to 28 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 8 wt. % to 28 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 10 wt. % to 28 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 4 wt. % to 15 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 6 wt. % to 12 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 4 wt. % to 10 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 4 wt. % to 8 wt. % zinc.

In one or more embodiments detailed herein, the variation of the zincweight percent is 12% or less between the surface and the thicknesscenter of the aluminum alloy strip.

In one or more embodiments detailed herein, the present invention is acast product comprising an aluminum alloy strip; wherein the aluminumalloy strip comprises: (i) 4 wt. % to 28 wt. % zinc; (ii) 1 wt. % to 3wt. % copper; and (iii) 1 wt. % to 3 wt. % magnesium; and wherein avariation of a weight percent of the zinc is 15% or less between asurface and a thickness center of the aluminum alloy strip.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 4 wt. % to 15 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 4 wt. % to 12 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 4 wt. % to 10 wt. % zinc.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 1 wt. % to 2.5 wt. % copper. In one or more embodimentsdetailed herein, the aluminum alloy strip comprises 1 wt. % to 2.0 wt. %copper. In one or more embodiments detailed herein, the aluminum alloystrip comprises 1 wt. % to 1.5 wt. % copper.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 1 wt. % to 2.5 wt. % magnesium. In one or more embodimentsdetailed herein, the aluminum alloy strip comprises 1 wt. % to 2.0 wt. %magnesium. In one or more embodiments detailed herein, the aluminumalloy strip comprises 1 wt. % to 1.5 wt. % magnesium.

In one or more embodiments detailed herein, the cast product comprisesan aluminum alloy strip; wherein the aluminum alloy strip comprises: 4wt. % to 28 wt. % zinc and 1 wt. % to 3 wt. % copper. In one or moreembodiments detailed herein, a variation of a weight percent of the zincis 15% or less between a surface and a thickness center of the aluminumalloy strip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a non-limiting method of making the castproduct;

FIG. 2 is an enlarged cross-sectional schematic of the molten metaldelivery tip and rolls shown in FIG. 1;

FIG. 3 shows the variation in zinc weight percentage from surface to athickness depth of 3,000 micrometers in a cast product;

FIG. 4 shows the variation in zinc weight percentage from surface to athickness depth of 3,000 micrometers in a cast product;

FIG. 5 shows the variation in zinc weight percentage from surface to athickness depth of 3,000 micrometers in a cast product;

FIG. 6 shows the variation in zinc weight percentage from surface to athickness depth of 3,000 micrometers in a cast product;

FIG. 7 shows the variation in zinc weight percentage from surface to athickness depth of 3,000 micrometers in a cast product;

FIG. 8 shows the variation in zinc weight percentage from surface to athickness depth of 3,000 micrometers in a cast product;

FIG. 9 shows the variation in zinc weight percentage from surface to athickness depth of 3,000 micrometers in a cast product;

FIG. 10 shows the variation in zinc weight percentage from surface to athickness depth of 3,000 micrometers in a cast product;

FIG. 11 shows the variation in zinc weight percentage through depth of aprior art ingot cast by direct chill casting;

FIG. 12 shows the variation in zinc weight percentage through depth of aprior art cast product;

FIG. 13 shows the weight percentages of zinc, magnesium and copperacross grains from the surface to 200 micrometers thickness depth in acast product according to an embodiment of the present invention.

FIG. 14 shows the weight percentages of the zinc, magnesium and copperacross grains through thickness depth for a direct chill cast prior artproduct;

FIG. 15 shows the structure of a cast product according to an embodimentof the present invention;

FIG. 16 shows the structure of a cast product according to an embodimentof the present invention; and

FIG. 17 shows the structure of a cast product according to an embodimentof the present invention.

The figures constitute a part of this specification and includeillustrative embodiments of the present invention and illustrate variousobjects and features thereof. Further, the figures are not necessarilyto scale, some features may be exaggerated to show details of particularcomponents. In addition, any measurements, specifications and the likeshown in the figures are intended to be illustrative, and notrestrictive. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

The present invention will be further explained with reference to theattached drawings, wherein like structures are referred to by likenumerals throughout the several views. The drawings shown are notnecessarily to scale, with emphasis instead generally being placed uponillustrating the principles of the present invention. Further, somefeatures may be exaggerated to show details of particular components.

DETAILED DESCRIPTION OF THE INVENTION

Among those benefits and improvements that have been disclosed, otherobjects and advantages of this invention will become apparent from thefollowing description taken in conjunction with the accompanyingfigures. Detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely illustrative of the invention that may be embodied in variousforms. In addition, each of the examples given in connection with thevarious embodiments of the invention which are intended to beillustrative, and not restrictive.

Throughout the specification and claims, the following terms take themeanings explicitly associated herein, unless the context clearlydictates otherwise. The phrases “in one embodiment” and “in someembodiments” as used herein do not necessarily refer to the sameembodiment(s), though they may. Furthermore, the phrases “in anotherembodiment” and “in some other embodiments” as used herein do notnecessarily refer to a different embodiment, although they may. Thus, asdescribed below, various embodiments of the invention may be readilycombined, without departing from the scope or spirit of the invention.

In addition, as used herein, the term “or” is an inclusive “or”operator, and is equivalent to the term “and/or,” unless the contextclearly dictates otherwise. The term “based on” is not exclusive andallows for being based on additional factors not described, unless thecontext clearly dictates otherwise. In addition, throughout thespecification, the meaning of “a,” “an,” and “the” include pluralreferences. The meaning of “in” includes “in” and “on.”

As used herein, the term “at least one of A, B, or C” and the like,means “only A”, “only B”, “only C”, or “any combination of A, B, and C.”

In one or more embodiments detailed herein, the present invention is acast product comprising an aluminum alloy strip; wherein the aluminumalloy strip comprises: 4 wt. % to 28 wt. % zinc; and wherein a variationof a weight percent of the zinc is 15% or less between a surface and athickness center of the aluminum alloy strip.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 6 wt. % to 28 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 8 wt. % to 28 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 10 wt. % to 28 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 4 wt. % to 15 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 6 wt. % to 12 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 4 wt. % to 10 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 4 wt. % to 8 wt. % zinc.

In one or more embodiments detailed herein, the variation of the zincweight percent is 12% or less between the surface and the thicknesscenter of the aluminum alloy strip.

In one or more embodiments detailed herein, the present invention is acast product comprising an aluminum alloy strip; wherein the aluminumalloy strip comprises: (i) 4 wt. % to 28 wt. % zinc; (ii) 1 wt. % to 3wt. % copper; and (iii) 1 wt. % to 3 wt. % magnesium; and wherein avariation of a weight percent of the zinc is 15% or less between asurface and a thickness center of the aluminum alloy strip.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 4 wt. % to 15 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 4 wt. % to 12 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 4 wt. % to 10 wt. % zinc.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 1 wt. % to 2.5 wt. % copper. In one or more embodimentsdetailed herein, the aluminum alloy strip comprises 1 wt. % to 2.0 wt. %copper. In one or more embodiments detailed herein, the aluminum alloystrip comprises 1 wt. % to 1.5 wt. % copper.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 1 wt. % to 2.5 wt. % magnesium. In one or more embodimentsdetailed herein, the aluminum alloy strip comprises 1 wt. % to 2.0 wt. %magnesium. In one or more embodiments detailed herein, the aluminumalloy strip comprises 1 wt. % to 1.5 wt. % magnesium.

In one or more embodiments detailed herein, the cast product comprisesan aluminum alloy strip; wherein the aluminum alloy strip comprises: 4wt. % to 28 wt. % zinc and 1 wt. % to 3 wt. % copper. In one or moreembodiments detailed herein, a variation of a weight percent of the zincis 15% or less between a surface and a thickness center of the aluminumalloy strip.

In one or more embodiments detailed herein, the present invention is acast product comprising an aluminum alloy strip; wherein the aluminumalloy strip comprises: 4 wt. % to 25 wt. % zinc; and wherein a variationof a weight percent of the zinc is 15% or less between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 6 wt. % to 25 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 8 wt. % to 25 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 10 wt. % to 25 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 4 wt. % to 15 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 4 wt. % to 12 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 4 wt. % to 10 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 4 wt. % to 8 wt. % zinc.

In one or more embodiments detailed herein, the variation of the zincweight percent is 12% or less between the surface and the thicknessdepth of 3,000 micrometers in the aluminum alloy strip.

In one or more embodiments detailed herein, the present invention is acast product comprising an aluminum alloy strip; wherein the aluminumalloy strip comprises: (i) 4 wt. % to 25 wt. % zinc; (ii) 1 wt. % to 3wt. % copper; and (iii) 1 wt. % to 3 wt. % magnesium; and wherein avariation of a weight percent of the zinc is 15% or less between asurface and a thickness depth of 3,000 micrometers in the aluminum alloystrip.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 4 wt. % to 15 wt. % zinc. In one or more embodiments detailedherein, the aluminum alloy strip comprises 4 wt. % to 12 wt. % zinc. Inone or more embodiments detailed herein, the aluminum alloy stripcomprises 4 wt. % to 10 wt. % zinc.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 1 wt. % to 2.5 wt. % copper. In one or more embodimentsdetailed herein, the aluminum alloy strip comprises 1 wt. % to 2.0 wt. %copper. In one or more embodiments detailed herein, the aluminum alloystrip comprises 1 wt. % to 1.5 wt. % copper.

In one or more embodiments detailed herein, the aluminum alloy stripcomprises 1 wt. % to 2.5 wt. % magnesium. In one or more embodimentsdetailed herein, the aluminum alloy strip comprises 1 wt. % to 2.0 wt. %magnesium. In one or more embodiments detailed herein, the aluminumalloy strip comprises 1 wt. % to 1.5 wt. % magnesium.

As used herein, the term “aluminum alloy” means an aluminum metal withsoluble elements either in the aluminum lattice or in a phase withinaluminum. Elements may include aluminum, copper, iron, magnesium,nickel, silicon, zinc, chromium, manganese, titanium, vanadium,zirconium, tin, scandium, lithium. Elements are added to influencephysical properties of the aluminum alloy and performancecharacteristics.

As used herein, the phrase “7xxx aluminum alloys” and the like means analuminum alloy selected from 7xxx aluminum alloys registered with theAluminum Association and unregistered variants of the same.

As used herein, the term “cast product” means a product that has beenproduced by a casting method such as continuous casting as detailed inU.S. Pat. Nos. 6,672,368 and 7,125,612. In one or more embodimentsdetailed herein, the term “cast product” includes a product producedfrom the “cast product”. In one or more embodiments, the term “castproduct” includes a rolled product produced from the “cast product”.

As used herein, the term “variation” of the weight percent of analloying element in a specified thickness depth has units of “%” and iscalculated according to the following equation:

(maximum weight percent of alloying element in the specified thicknessdepth−minimum weight percent of the alloying element in the specifiedthickness depth)/(average weight percent of the alloying element in thespecified thickness depth)*100.

As used herein, the term “centerline segregation” means the enrichmentor depletion of alloying elements in a central portion of an aluminumalloy strip. In embodiments, centerline segregation is determined basedon a variation of the weight percent of an alloying element in aspecified thickness depth of an aluminum alloy strip. In one or moreembodiments detailed herein, centerline segregation is determined basedon a variation of weight percent of an alloying element of greater than15% between a surface and a thickness depth of 3,000 micrometers. In oneor more embodiments detailed herein, centerline segregation isdetermined based on a variation of weight percent of an alloying elementof greater than 15% between a surface and a thickness center of thealuminum alloy strip.

As used herein, the “weight percent of an alloying element” in aspecified thickness depth is determined using the “macro-segregationprocedure” detailed herein.

As used herein, the term “strip” may be of any suitable thickness, andis generally of sheet gauge (0.006 inch to 0.249 inch) or thin-plategauge (0.250 inch to 0.400 inch), i.e., has a thickness in the range offrom 0.006 inch to 0.400 inch. In one embodiment, the strip has athickness of at least 0.040 inch. In one embodiment, the strip has athickness of less than 0.320 inch. In one or more embodiments detailedherein, the strip has a thickness of from 0.0070 to 0.18 inches. In oneor more embodiments detailed herein, the strip has a thickness of from0.08 to 0.2 inches.

As used herein, “surface” means a top surface or a bottom surface of thecast product.

As used herein, “thickness center” means a depth of half the totalthickness of the cast product or half thickness (t/2).

In one or more embodiments detailed herein, the aluminum alloy strip mayinclude any aluminum alloy having 4 wt. % to 28 wt. % zinc. In one ormore embodiments detailed herein, the aluminum alloy strip may includeat least one of 1 wt. % to 3 wt. % copper and 1 wt. % to 3 wt. %magnesium. In one or more embodiments detailed herein, the aluminumalloy may include 7xxx (zinc based) aluminum alloys.

In one or more embodiments detailed herein, the aluminum alloy strip has4 wt. % to 28 wt. % zinc. In one or more embodiments detailed herein,the aluminum alloy strip has 4 wt. % to 27 wt. % zinc. In one or moreembodiments detailed herein, the aluminum alloy strip has 4 wt. % to 25wt. % zinc. In one or more embodiments detailed herein, the aluminumalloy strip has 4 wt. % to 22 wt. % zinc. In one or more embodimentsdetailed herein, the aluminum alloy strip has 4 wt. % to 20 wt. % zinc.In one or more embodiments detailed herein, the aluminum alloy strip has4 wt. % to 18 wt. % zinc. In one or more embodiments detailed herein,the aluminum alloy strip has 4 wt. % to 15 wt. % zinc. In one or moreembodiments detailed herein, the aluminum alloy strip has 4 wt. % to 13wt. % zinc. In one or more embodiments detailed herein, the aluminumalloy strip has 4 wt. % to 11 wt. % zinc. In one or more embodimentsdetailed herein, the aluminum alloy strip has 4 wt. % to 10 wt. % zinc.In one or more embodiments detailed herein, the aluminum alloy strip has4 wt. % to 9 wt. % zinc. In one or more embodiments detailed herein, thealuminum alloy strip has 4 wt. % to 8 wt. % zinc. In one or moreembodiments detailed herein, the aluminum alloy strip has 4 wt. % to 7wt. % zinc. In one or more embodiments detailed herein, the aluminumalloy strip has 4 wt. % to 6 wt. % zinc. In one or more embodimentsdetailed herein, the aluminum alloy strip has 4 wt. % to 5 wt. % zinc.

In one or more embodiments detailed herein, the aluminum alloy strip has5 wt. % to 28 wt. % zinc. In one or more embodiments detailed herein,the aluminum alloy strip has 6 wt. % to 28 wt. % zinc. In one or moreembodiments detailed herein, the aluminum alloy strip has 7 wt. % to 28wt. % zinc. In one or more embodiments detailed herein, the aluminumalloy strip has 8 wt. % to 28 wt. % zinc. In one or more embodimentsdetailed herein, the aluminum alloy strip has 9 wt. % to 28 wt. % zinc.In one or more embodiments detailed herein, the aluminum alloy strip has10 wt. % to 28 wt. % zinc. In one or more embodiments detailed herein,the aluminum alloy strip has 11 wt. % to 28 wt. % zinc. In one or moreembodiments detailed herein, the aluminum alloy strip has 13 wt. % to 28wt. % zinc. In one or more embodiments detailed herein, the aluminumalloy strip has 15 wt. % to 28 wt. % zinc. In one or more embodimentsdetailed herein, the aluminum alloy strip has 18 wt. % to 28 wt. % zinc.In one or more embodiments detailed herein, the aluminum alloy strip has20 wt. % to 28 wt. % zinc. In one or more embodiments detailed herein,the aluminum alloy strip has 22 wt. % to 28 wt. % zinc.

In one or more embodiments detailed herein, the aluminum alloy strip has5 wt. % to 27 wt. % zinc. In one or more embodiments detailed herein,the aluminum alloy strip has 7 wt. % to 25 wt. % zinc. In one or moreembodiments detailed herein, the aluminum alloy strip has 8 wt. % to 23wt. % zinc. In one or more embodiments detailed herein, the aluminumalloy strip has 9 wt. % to 20 wt. % zinc. In one or more embodimentsdetailed herein, the aluminum alloy strip has 10 wt. % to 18 wt. % zinc.In one or more embodiments detailed herein, the aluminum alloy strip has12 wt. % to 15 wt. % zinc.

In one or more embodiments detailed herein, the aluminum alloy strip has1 wt. % to 2.8 wt. % copper. In one or more embodiments detailed herein,the aluminum alloy strip has 1 wt. % to 2.6 wt. % copper. In one or moreembodiments detailed herein, the aluminum alloy strip has 1 wt. % to 2.4wt. % copper. In one or more embodiments detailed herein, the aluminumalloy strip has 1 wt. % to 2.2 wt. % copper. In one or more embodimentsdetailed herein, the aluminum alloy strip has 1 wt. % to 2.0 wt. %copper. In one or more embodiments detailed herein, the aluminum alloystrip has 1 wt. % to 1.8 wt. % copper. In one or more embodimentsdetailed herein, the aluminum alloy strip has 1 wt. % to 1.6 wt. %copper. In one or more embodiments detailed herein, the aluminum alloystrip has 1 wt. % to 1.4 wt. % copper. In one or more embodimentsdetailed herein, the aluminum alloy strip has 1 wt. % to 1.2 wt. %copper.

In one or more embodiments detailed herein, the aluminum alloy strip has1.2 wt. % to 3 wt. % copper. In one or more embodiments detailed herein,the aluminum alloy strip has 1.4 wt. % to 3 wt. % copper. In one or moreembodiments detailed herein, the aluminum alloy strip has 1.6 wt. % to 3wt. % copper. In one or more embodiments detailed herein, the aluminumalloy strip has 1.8 wt. % to 3 wt. % copper. In one or more embodimentsdetailed herein, the aluminum alloy strip has 2.0 wt. % to 3 wt. %copper. In one or more embodiments detailed herein, the aluminum alloystrip has 2.2 wt. % to 3 wt. % copper. In one or more embodimentsdetailed herein, the aluminum alloy strip has 2.4 wt. % to 3 wt. %copper. In one or more embodiments detailed herein, the aluminum alloystrip has 2.6 wt. % to 3 wt. % copper. In one or more embodimentsdetailed herein, the aluminum alloy strip has 2.8 wt. % to 3 wt. %copper.

In one or more embodiments detailed herein, the aluminum alloy strip has1.2 wt. % to 2.8 wt. % copper. In one or more embodiments detailedherein, the aluminum alloy strip has 1.4 wt. % to 2.6 wt. % copper. Inone or more embodiments detailed herein, the aluminum alloy strip has1.6 wt. % to 2.4 wt. % copper. In one or more embodiments detailedherein, the aluminum alloy strip has 1.8 wt. % to 2.2 wt. % copper.

In one or more embodiments detailed herein, the aluminum alloy strip has1 wt. % to 2.8 wt. % magnesium. In one or more embodiments detailedherein, the aluminum alloy strip has 1 wt. % to 2.6 wt. % magnesium. Inone or more embodiments detailed herein, the aluminum alloy strip has 1wt. % to 2.4 wt. % magnesium. In one or more embodiments detailedherein, the aluminum alloy strip has 1 wt. % to 2.2 wt. % magnesium. Inone or more embodiments detailed herein, the aluminum alloy strip has 1wt. % to 2.0 wt. % magnesium. In one or more embodiments detailedherein, the aluminum alloy strip has 1 wt. % to 1.8 wt. % magnesium. Inone or more embodiments detailed herein, the aluminum alloy strip has 1wt. % to 1.6 wt. % magnesium. In one or more embodiments detailedherein, the aluminum alloy strip has 1 wt. % to 1.4 wt. % magnesium. Inone or more embodiments detailed herein, the aluminum alloy strip has 1wt. % to 1.2 wt. % magnesium.

In one or more embodiments detailed herein, the aluminum alloy strip has1.2 wt. % to 3 wt. % magnesium. In one or more embodiments detailedherein, the aluminum alloy strip has 1.4 wt. % to 3 wt. % magnesium. Inone or more embodiments detailed herein, the aluminum alloy strip has1.6 wt. % to 3 wt. % magnesium. In one or more embodiments detailedherein, the aluminum alloy strip has 1.8 wt. % to 3 wt. % magnesium. Inone or more embodiments detailed herein, the aluminum alloy strip has2.0 wt. % to 3 wt. % magnesium. In one or more embodiments detailedherein, the aluminum alloy strip has 2.2 wt. % to 3 wt. % magnesium. Inone or more embodiments detailed herein, the aluminum alloy strip has2.4 wt. % to 3 wt. % magnesium. In one or more embodiments detailedherein, the aluminum alloy strip has 2.6 wt. % to 3 wt. % magnesium. Inone or more embodiments detailed herein, the aluminum alloy strip has2.8 wt. % to 3 wt. % magnesium.

In one or more embodiments detailed herein, the aluminum alloy strip has1.2 wt. % to 2.8 wt. % magnesium. In one or more embodiments detailedherein, the aluminum alloy strip has 1.4 wt. % to 2.6 wt. % magnesium.In one or more embodiments detailed herein, the aluminum alloy strip has1.6 wt. % to 2.4 wt. % magnesium. In one or more embodiments detailedherein, the aluminum alloy strip has 1.8 wt. % to 2.2 wt. % magnesium.

In one or more embodiments detailed herein, the aluminum alloy strip has0.1 wt. % to 1.0 wt. % manganese. In one or more embodiments detailedherein, the aluminum alloy strip has 0.2 wt. % to 1.0 wt. % manganese.In one or more embodiments detailed herein, the aluminum alloy strip has0.4 wt. % to 1.0 wt. % manganese. In one or more embodiments detailedherein, the aluminum alloy strip has 0.6 wt. % to 1.0 wt. % manganese.In one or more embodiments detailed herein, the aluminum alloy strip has0.8 wt. % to 1.0 wt. % manganese.

In one or more embodiments detailed herein, the aluminum alloy strip has0.1 wt. % to 0.8 wt. % manganese. In one or more embodiments detailedherein, the aluminum alloy strip has 0.1 wt. % to 0.9 wt. % manganese.In one or more embodiments detailed herein, the aluminum alloy strip has0.1 wt. % to 0.7 wt. % manganese. In one or more embodiments detailedherein, the aluminum alloy strip has 0.1 wt. % to 0.5 wt. % manganese.In one or more embodiments detailed herein, the aluminum alloy strip has0.1 wt. % to 0.3 wt. % manganese.

In one or more embodiments detailed herein, the aluminum alloy strip has0.05 wt. % to 0.3 wt. % chromium. In one or more embodiments detailedherein, the aluminum alloy strip has 0.1 wt. % to 0.3 wt. % chromium. Inone or more embodiments detailed herein, the aluminum alloy strip has0.15 wt. % to 0.3 wt. % chromium. In one or more embodiments detailedherein, the aluminum alloy strip has 0.2 wt. % to 0.3 wt. % chromium. Inone or more embodiments detailed herein, the aluminum alloy strip has0.25 wt. % to 0.3 wt. % chromium.

In one or more embodiments detailed herein, the aluminum alloy strip has0.05 wt. % to 0.25 wt. % chromium. In one or more embodiments detailedherein, the aluminum alloy strip has 0.05 wt. % to 0.2 wt. % chromium.In one or more embodiments detailed herein, the aluminum alloy strip has0.05 wt. % to 0.15 wt. % chromium. In one or more embodiments detailedherein, the aluminum alloy strip has 0.05 wt. % to 0.1 wt. % chromium.In one or more embodiments detailed herein, the aluminum alloy strip has0.15 wt. % to 0.25 wt. % chromium.

In one or more embodiments detailed herein, the aluminum alloy strip has0.04 wt. % to 0.25 wt. % zirconium. In one or more embodiments detailedherein, the aluminum alloy strip has 0.04 wt. % to 0.2 wt. % zirconium.In one or more embodiments detailed herein, the aluminum alloy strip has0.04 wt. % to 0.18 wt. % zirconium. In one or more embodiments detailedherein, the aluminum alloy strip has 0.04 wt. % to 0.15 wt. % zirconium.In one or more embodiments detailed herein, the aluminum alloy strip has0.04 wt. % to 0.1 wt. % zirconium.

In one or more embodiments detailed herein, the aluminum alloy strip has0.1 wt. % to 0.25 wt. % zirconium. In one or more embodiments detailedherein, the aluminum alloy strip has 0.15 wt. % to 0.25 wt. % zirconium.In one or more embodiments detailed herein, the aluminum alloy strip has0.2 wt. % to 0.25 wt. % zirconium.

In one or more embodiments detailed herein, the aluminum alloy strip has0.07 wt. % to 0.14 wt. % zirconium.

In one or more embodiments detailed herein, the aluminum alloy stripincludes at least one of zinc, copper, magnesium, manganese, chromium,or zirconium. In one or more embodiments detailed herein, the aluminumalloy strip is free of at least one of copper, magnesium, manganese,chromium, or zirconium.

In one or more embodiments detailed herein, the aluminum alloy strip maycontain secondary elements and/or other elements. As used herein,“secondary elements” are Fe, Si, and/or Ti. As used herein, “otherelements” includes any elements of the periodic table other thanaluminum (Al), Zn, Cu, Mn, Cr, Zr, Mg, Fe, Si, and/or Ti.

In one or more embodiments detailed herein, a variation of the zincweight percent between a surface and a thickness center of the aluminumalloy strip is 15% or less. In one or more embodiments detailed herein,a variation of the zinc weight percent between a surface and a thicknesscenter of the aluminum alloy strip is 14% or less. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is13% or less. In one or more embodiments detailed herein, a variation ofthe zinc weight percent between a surface and a thickness center of thealuminum alloy strip is 12% or less. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness center of the aluminum alloy strip is 11% or less. In one ormore embodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is10% or less. In one or more embodiments detailed herein, a variation ofthe zinc weight percent between a surface and a thickness center of thealuminum alloy strip is 9% or less. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness center of the aluminum alloy strip is 8% or less. In one ormore embodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is7% or less. In one or more embodiments detailed herein, a variation ofthe zinc weight percent between a surface and a thickness center of thealuminum alloy strip is 6% or less. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness center of the aluminum alloy strip is 5% or less. In one ormore embodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is4% or less. In one or more embodiments detailed herein, a variation ofthe zinc weight percent between a surface and a thickness center of thealuminum alloy strip is 3% or less. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness center of the aluminum alloy strip is 2% or less.

In one or more embodiments detailed herein, a variation of the zincweight percent between a surface and a thickness center of the aluminumalloy strip is 0.1% to 15%. In one or more embodiments detailed herein,a variation of the zinc weight percent between a surface and a thicknesscenter of the aluminum alloy strip is 0.1% to 14%. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is0.1% to 13%. In one or more embodiments detailed herein, a variation ofthe zinc weight percent between a surface and a thickness center of thealuminum alloy strip is 0.1% to 12%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness center of the aluminum alloy strip is 0.1% to 11%. In one ormore embodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is0.1% to 10%. In one or more embodiments detailed herein, a variation ofthe zinc weight percent between a surface and a thickness center of thealuminum alloy strip is 0.1% to 9%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness center of the aluminum alloy strip is 0.1% to 8%. In one ormore embodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is0.1% to 7%. In one or more embodiments detailed herein, a variation ofthe zinc weight percent between a surface and a thickness center of thealuminum alloy strip is 0.1% to 6%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness center of the aluminum alloy strip is 0.1% to 5%. In one ormore embodiments detailed herein, a variation of the zinc weight percentis 0.1% to 4% between a surface and a thickness center of the aluminumalloy strip.

In one or more embodiments detailed herein, a variation of the zincweight percent between a surface and a thickness center of the aluminumalloy strip is 1% to 15%. In one or more embodiments detailed herein, avariation of the zinc weight percent between a surface and a thicknesscenter of the aluminum alloy strip is 2% to 15%. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is3% to 15%. In one or more embodiments detailed herein, a variation ofthe zinc weight percent between a surface and a thickness center of thealuminum alloy strip is 4% to 15%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness center of the aluminum alloy strip is 5% to 15%. In one ormore embodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is6% to 15%. In one or more embodiments detailed herein, a variation ofthe zinc weight percent between a surface and a thickness center of thealuminum alloy strip is 7% to 15%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness center of the aluminum alloy strip is 8% to 15%. In one ormore embodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is9% to 15%. In one or more embodiments detailed herein, a variation ofthe zinc weight percent between a surface and a thickness center of thealuminum alloy strip is 10% to 15%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness center of the aluminum alloy strip is 11% to 15%. In one ormore embodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness center of the aluminum alloy strip is12% to 15%.

In one or more embodiments detailed herein, a variation of the zincweight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 15% or less. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 14% or less. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 13%or less. In one or more embodiments detailed herein, a variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 12% or less. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 11% or less. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 10%or less. In one or more embodiments detailed herein, a variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 9% or less. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 8% or less. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 7%or less. In one or more embodiments detailed herein, a variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 6% or less. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 5% or less. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 4%or less. In one or more embodiments detailed herein, a variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 3% or less. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 2% or less.

In one or more embodiments detailed herein, a variation of the zincweight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 0.1% to 15%. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 0.1% to 14%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 0.1%to 13%. In one or more embodiments detailed herein, a variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 0.1% to 12%. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 0.1% to 11%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 0.1%to 10%. In one or more embodiments detailed herein, a variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 0.1% to 9%. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 0.1% to 8%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 0.1%to 7%. In one or more embodiments detailed herein, a variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 0.1% to 6%. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 0.1% to 5%. In one or more embodiments detailedherein, a variation of the zinc weight percent is 0.1% to 4% between asurface and a thickness depth of 3,000 micrometers in the aluminum alloystrip.

In one or more embodiments detailed herein, a variation of the zincweight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 1% to 15%. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 2% to 15%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 3%to 15%. In one or more embodiments detailed herein, a variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 4% to 15%. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 5% to 15%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 6%to 15%. In one or more embodiments detailed herein, a variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 7% to 15%. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 8% to 15%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 9%to 15%. In one or more embodiments detailed herein, a variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers in the aluminum alloy strip is 10% to 15%. In one or moreembodiments detailed herein, a variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thealuminum alloy strip is 11% to 15%. In one or more embodiments detailedherein, a variation of the zinc weight percent between a surface and athickness depth of 3,000 micrometers in the aluminum alloy strip is 12%to 15%.

In one or more embodiments detailed herein, the aluminum alloy has azinc weight percent of 4% to 28% or any other weight percent rangedetailed herein and does not exhibit centerline segregation.

Non-Limiting Method for Producing Aluminum Alloy Strip

In embodiments, the casting of the aluminum alloy strip detailed hereinmay be accomplished via a continuous casting apparatus capable ofproducing continuously cast products that are solidified at highsolidification rates. One example of a continuous casting apparatuscapable of achieving the above-described solidification rates is theapparatus described in U.S. Pat. Nos. 6,672,368 and 7,125,612,incorporated by reference in their entirety. In one or more embodimentsdetailed herein, the aluminum alloy strip is continuously cast using theMicromill™ process described in U.S. Pat. Nos. 6,672,368 and 7,125,612.

In embodiments, as illustrated in FIGS. 1-2, a molten aluminum alloymetal M may be stored in a hopper H (or tundish) and delivered through afeed tip T, in a direction B, to a pair of rolls R₁ and R₂, havingrespective roll surfaces D₁ and D₂, which are each rotated in respectivedirections A₁ and A₂, to produce a solid cast product S. In one or moreembodiments detailed herein, gaps G₁ and G₂ may be maintained betweenthe feed tip T and respective rolls R₁ and R₂ as small as possible toprevent molten metal from leaking out, and to minimize the exposure ofthe molten metal to the atmosphere, while maintaining a separationbetween the feed tip T and rolls R₁ and R₂. A plane L through thecenterline of the rolls R₁ and R₂ passes through a region of minimumclearance between the rolls R₁ and R₂ referred to as the roll nip N.

In one or more embodiments detailed herein, during casting, the moltenmetal M directly contacts the cooled rolls R₁ and R₂ at regions 2 and 4,respectively. Upon contact with the rolls R₁ and R₂, the metal M beginsto cool and solidify. The cooling metal produces an upper shell 6 ofsolidified metal adjacent the roll R₁ and a lower shell 8 of solidifiedmetal adjacent to the roll R₂. The thickness of the shells 6 and 8increases as the metal M advances towards the nip N. Large dendrites 10of solidified metal (not shown to scale) may be produced at theinterfaces between each of the upper and lower shells 6 and 8 and themolten metal M. The large dendrites 10 may be broken and dragged into acenter portion 12 of the slower moving flow of the molten metal M andmay be carried in the direction of arrows C₁ and C₂. The dragging actionof the flow can cause the large dendrites 10 to be broken further intosmaller dendrites 14 (not shown to scale). In the central portion 12upstream of the nip N referred to as a region 16, the metal M issemi-solid and may include a solid component (the solidified smalldendrites 14) and a molten metal component. The metal M in the region 16may have a mushy consistency due in part to the dispersion of the smalldendrites 14 therein. At the location of the nip N, some of the moltenmetal may be squeezed backwards in a direction opposite to the arrows C₁and C₂. The forward rotation of the rolls R₁ and R₂ at the nip Nadvances substantially only the solid portion of the metal (the upperand lower shells 6 and 8 and the small dendrites 14 in the centralportion 12) while forcing molten metal in the central portion 12upstream from the nip N such that the metal may be completely solid asit leaves the point of the nip N. In this manner and in one or moreembodiments detailed herein, a freeze front of metal may be formed atthe nip N. Downstream of the nip N, the central portion 12 may be asolid central portion, 18 containing the small dendrites 14 sandwichedbetween the upper shell 6 and the lower shell 8. In the central portion,18, the small dendrites 14 may be 20 microns to 50 microns in size andhave a generally globular shape. The three portions, of the upper andlower shells 6 and 8 and the solidified central portion 18, constitute asingle, solid cast product (S in FIG. 1 and element 20 in FIG. 2). Thus,the aluminum alloy cast product 20 may include a first portion of analuminum alloy and a second portion of the aluminum alloy (correspondingto the shells 6 and 8) with an intermediate portion (the solidifiedcentral portion 18) therebetween. The solid central portion 18 mayconstitute 20 percent to 30 percent of the total thickness of the castproduct 20.

The rolls R₁ and R₂ may serve as heat sinks for the heat of the moltenmetal M. In one embodiment, heat may be transferred from the moltenmetal M to the rolls R₁ and R₂ in a uniform manner to ensure uniformityin the surface of the cast product 20. Surfaces D₁ and D₂ of therespective rolls R₁ and R₂ may be made from steel, copper, nickel, orother suitable material and may be textured and may include surfaceirregularities (not shown) which may contact the molten metal M.

The control, maintenance and selection of the appropriate speed of therolls R₁ and R₂ may impact the ability to continuously cast products.The roll speed determines the speed that the molten metal M advancestowards the nip N. If the speed is too slow, the large dendrites 10 willnot experience sufficient forces to become entrained in the centralportion 12 and break into the small dendrites 14. In one or moreembodiments detailed herein, the roll speed may be selected such that afreeze front, or point of complete solidification, of the molten metal Mmay form at the nip N. Accordingly, the present casting apparatus andmethods may be suited for operation at high speeds such as those rangingfrom 25 to 500 feet per minute; alternatively from 40 to 500 feet perminute; alternatively from 40 to 400 feet per minute; alternatively from100 to 400 feet per minute; and alternatively from 150 to 300 feet perminute. The linear rate per unit area that molten aluminum is deliveredto the rolls R₁ and R₂ may be less than the speed of the rolls R₁ and R₂or about one quarter of the roll speed.

Continuous casting of aluminum alloys according to the presentdisclosure may be achieved by initially selecting the desired dimensionof the nip N corresponding to the desired gauge of the cast product S.The speed of the rolls R₁ and R₂ may be increased to a desiredproduction rate or to a speed which is less than the speed which causesthe roll separating force increases to a level which indicates thatrolling is occurring between the rolls R₁ and R₂. Casting at the ratescontemplated by an embodiment of the present invention (i.e. 25 to 400feet per minute) solidifies the aluminum alloy cast product about 1000times faster than aluminum alloy cast as an ingot cast and improves theproperties of the cast product over aluminum alloys cast as an ingot.The rate at which the molten metal is cooled may be selected to achieverapid solidification of the outer regions of the metal. Indeed, thecooling of the outer regions of metal may occur at a rate of at least1000 degrees Celsius per second.

The continuous cast strip may be of any suitable thickness, and isgenerally of sheet gauge (0.006 inch to 0.249 inch) or thin-plate gauge(0.250 inch to 0.400 inch), i.e., has a thickness in the range of from0.006 inch to 0.400 inch. In one embodiment, the strip has a thicknessof at least 0.040 inch. In one embodiment, the strip has a thickness ofless than 0.320 inch.

Macro-Segregation Procedure

Samples are first mounted and polished in Lucite using standardmetallographic preparation techniques for aluminum. An Electron ProbeMicro Analyzer (“EPMA”) is used to profile the distribution of thealloying elements across a thickness to show the macro-segregation ofthe alloying elements.

EPMA line scans are set with an initial spot of 100 micrometers diameterabout 50 micrometers from the sample surface moving in the thicknessdirection until the other surface is reached. The defocused beam spotsare calculated to maintain a 50 micrometer separation to provide 50%overlap between points.

A JEOL JXA 8530F Field Emission Electron Probe Microanalyzer Hyperprobewith 4 Wave dispersive spectrometers and JEOL SDD-EDS are used to gatherthe data. The operating conditions are:

Accelerating Voltage: 15 kV

Beam Intensity: 100 nA

Defocus electron beam: 100 μm

Line scan profile step 50 μm

Analyzed elements may include: Ti, Zr, Mg, Si, Mn, Fe, Cu, Zn and Al

The wave dispersive spectrometer (WDS) crystal and spectrometers areused as detailed in the Table 1.

TABLE 1 Spectrometer Diffracting Crystal Counter Element 1 PETJ Gas Flow(P-10) Ti, Zr 2 TAP Gas Flow (P-10) Mg, Si 3 LIFH Sealed Xe gas Mn, Fe 4LIFL Sealed Xe gas Cu, Zn 5 SDD-EDS AlThe counting time is 10 seconds for all elements

A background measurement is collected every 50 spots for 5 seconds onpositive and negative background locations. Elements measured arequantitatively analyzed using the JEOL quant ZAF analysis package formetals with atomic number correction by Philibert-Tixier method andflourescence excitation correction by Reed method.

Alternately, the concentration of alloying elements through depth of asample was determined using a quantometer consistent with the methodused to analyze the samples from U.S. Pat. No. 6,672,368.

Micro-Segregation Procedure

Samples are first mounted and polished in Lucite using standardmetallographic preparation techniques for aluminum. An EPMA is used toprofile the distribution of the alloying elements across a thickness toshow the micro-segregation of the alloying elements.

EPMA line scans are set with a focused spot moving with a 1 micrometerstep across several grains to provide overlapping points throughmultiple grains.

A JEOL JXA 8530F Field Emission Electron Probe Microanalyzer Hyperprobewith 4 Wave dispersive spectrometers and JEOL SDD-EDS are used to gatherthe data. The operating conditions are:

Accelerating Voltage: 15 kV

Beam Intensity: 100 nA

Focused electron beam

Line scan profile step 1 μm

Analyzed elements may include: Ti, Zr, Mg, Si, Mn, Fe, Cu, Zn and Al

The WDS crystal and spectrometers are used as detailed in Table 1.

A background measurement is collected every 50 spots for 5 seconds onpositive and negative background locations. Elements measured arequantitatively analyzed using the JEOL quant ZAF analysis package formetals with atomic number correction by Philibert-Tixier method andflourescence excitation correction by Reed method.

Non-Limiting Examples

Aluminum alloy samples were cast using the apparatus detailed in U.S.Pat. No. 6,672,368 at a speed of 55 feet per minute to 85 feet perminute and had a final thickness detailed in the tables below. Theaverage weight percentages of the zinc, magnesium and copper from thesurface to 3,000 micrometers thickness depth in each sample wasdetermined using either the “macro-segregation” procedure detailedherein or via quantometer. Table 2 below shows the average weightpercentages of zinc, copper and magnesium from surface to a thicknessdepth of 3,000 micrometers in each of the cast samples and the methodused to determine the weight percentages in each sample:

TABLE 2 Avg. Thickness Zn Avg. Mg Avg. Cu Sample (mm) wt. % wt. % wt. %Method 1 3.5 4.26 1.50 1.59 macro-segregation procedure 2 3.3 5.60 1.852.28 quantometer 3 3.9 6.38 1.47 1.53 macro-segregation procedure 4 3.47.34 2.13 1.90 quantometer 5 3.4 7.56 1.94 2.42 quantometer 6 4.1 8.711.68 1.43 macro-segregation procedure 7 3.9 15.98 1.21 1.53macro-segregation procedure 8 3.6 27.46 0.97 1.64 macro-segregationprocedure

Table 3 below shows the variation of zinc weight percentages in each ofthe samples from surface to a thickness depth of 3,000 micrometers:

TABLE 3 Variation Sample Min. Zn wt. % Max. Zn wt. % Avg. Zn wt. % (%) 13.91 4.52 4.26 14.40 2 5.40 5.75 5.60 6.25 3 6.17 6.66 6.38 7.68 4 7.117.54 7.34 5.86 5 6.95 7.71 7.56 10.05 6 8.34 8.96 8.71 7.12 7 15.1017.09 15.98 12.45 8 25.53 29.70 27.46 15.19

The average weight percentages of the zinc, magnesium and copper fromthe surface to the thickness center in each sample were determined usingeither the “macro-segregation” procedure detailed herein or viaquantometer. Table 4 below shows the average weight percentages of zinc,copper and magnesium from surface to a thickness center in each of thecast samples and the method used to determine the weight percentages ineach sample:

TABLE 4 Avg. Thickness Zn Avg. Mg Avg. Cu Sample (mm) wt. % wt. % wt. %Method 1 3.5 4.27 1.50 1.61 macro-segregation procedure 2 3.3 5.64 1.862.28 quantometer 3 3.9 6.36 1.47 1.52 macro-segregation procedure 4 3.47.33 2.12 1.88 quantometer 5 3.4 7.54 1.93 2.42 quantometer 6 4.1 8.711.70 1.42 macro-segregation procedure 7 3.9 15.97 1.21 1.52macro-segregation procedure 8 3.6 27.54 0.99 1.70 macro-segregationprocedure

Table 5 below shows the variation of zinc weight percentages in each ofthe samples from surface to a thickness center in each sample:

TABLE 5 Variation Sample Min. Zn wt. % Max. Zn wt. % Avg. Zn wt. % (%) 13.91 4.52 4.27 14.29 2 5.48 5.75 5.64 4.79 3 6.17 6.57 6.36 6.29 4 7.117.54 7.33 5.87 5 6.95 7.71 7.54 10.08 6 8.44 8.96 8.71 5.97 7 15.1017.09 15.97 12.46 8 25.96 29.70 27.54 13.58

The data generated for each sample is plotted in FIGS. 3-10. Acomparison the weight percentages of the zinc, magnesium and copperthrough thickness of a direct chill cast prior art product and acontinuously cast prior art product of U.S. Pat. No. 6,672,368 are alsoincluded as FIGS. 11-12 for comparison.

As shown in FIGS. 3-10 and the tables above, the inventors surprisinglyfound that the variation of the zinc weight percent between a surfaceand a thickness depth of 3,000 micrometers in samples 1-7 according tothe present invention is less than 15%. Moreover, the variation of thezinc weight percent between a surface and a thickness depth of 3,000micrometers of sample 8 is greater than 15%. Similarly, based on visualinspection of FIGS. 11-12, the variation of the zinc weight percentbetween a surface and a thickness depth of 3,000 micrometers in thedirect chill cast prior art product and the continuously cast prior artproduct is greater than 15%.

As shown in FIGS. 3-10 and the tables above, the inventors surprisinglyfound that the variation of the zinc weight percent between a surfaceand a thickness center in samples 1-8 according to the present inventionis less than 15%. Moreover, based on visual inspection of FIGS. 11-12,the variation of the zinc weight percent between a surface and athickness center of the direct chill cast prior art product and thecontinuously cast prior art product is greater than 15%.

The weight percentages of the zinc, magnesium and copper across grainsfrom the surface to 200 micrometers thickness depth in sample 6 wasdetermined using the “micro-segregation” procedure detailed herein. Thedata is presented in FIG. 13. For comparison, the weight percentages ofthe zinc, magnesium and copper across grains through thickness for adirect chill cast prior art product are shown in FIG. 14. As shown inFIG. 13, the inventors surprisingly found that the weight percent of theprimary alloying elements Zn, Cu and Mg were substantially uniformacross the grains within the matrix with an increase in the weightpercent of the alloying elements at the positions of second phaseparticles at grain boundaries and within the grains.

FIG. 15 shows the structure of sample 6. The structure of samples ofaluminum alloys having average zinc contents of 16% and 25% cast usingthe apparatus detailed in U.S. Pat. No. 6,672,368 at a speed of 55 feetper minute are shown in FIGS. 16 and 17, respectively. FIGS. 15-17 showproducts of the present invention have a globular grain structure andare substantially free of micro-segregation. Moreover, as illustrated inFIGS. 15-17, the products of the present invention may be substantiallyfree of dendrites and consist primarily of globular non-dendriticgrains—i.e., a globular grain structure. Also, as shown by the absenceof shading within the grains of FIGS. 15-17 when the samples areobserved in polarized light, the products are substantially free ofmicro-segregation effects.

While a number of embodiments of the present invention have beendescribed, it is understood that these embodiments are illustrativeonly, and not restrictive, and that many modifications may becomeapparent to those of ordinary skill in the art. Further still, thevarious steps may be carried out in any desired order (and any desiredsteps may be added and/or any desired steps may be eliminated).

We claim:
 1. A cast product comprising: an aluminum alloy strip; whereinthe aluminum alloy strip comprises: 4 wt. % to 28 wt. % zinc; andwherein a variation of a weight percent of the zinc is 15% or lessbetween a surface and a thickness center of the aluminum alloy strip. 2.The cast product of claim 1, wherein the aluminum alloy strip comprises6 wt. % to 28 wt. % zinc.
 3. The cast product of claim 1, wherein thealuminum alloy strip comprises 8 wt. % to 28 wt. % zinc.
 4. The castproduct of claim 1, wherein the aluminum alloy strip comprises 10 wt. %to 28 wt. % zinc.
 5. The cast product of claim 1, wherein the aluminumalloy strip comprises 4 wt. % to 15 wt. % zinc
 6. The cast product ofclaim 1, wherein the aluminum alloy strip comprises 6 wt. % to 12 wt. %zinc.
 7. The cast product of claim 1, wherein the aluminum alloy stripcomprises 4 wt. % to 10 wt. % zinc.
 8. The cast product of claim 1,wherein the aluminum alloy strip comprises 4 wt. % to 8 wt. % zinc. 9.The cast product of claim 6, wherein the variation of the zinc weightpercent is 12% or less between the surface and the thickness center ofthe aluminum alloy strip.
 10. A cast product comprising: an aluminumalloy strip; wherein the aluminum alloy strip comprises: (i) 4 wt. % to28 wt. % zinc; (ii) 1 wt. % to 3 wt. % copper; and (iii) 1 wt. % to 3wt. % magnesium; wherein a variation of a weight percent of the zinc is15% or less between a surface and a thickness center of the aluminumalloy strip.
 11. The cast product of claim 10, wherein the aluminumalloy strip comprises 4 wt. % to 15 wt. % zinc
 12. The cast product ofclaim 10, wherein the aluminum alloy strip comprises 4 wt. % to 12 wt. %zinc.
 13. The cast product of claim 10, wherein the aluminum alloy stripcomprises 4 wt. % to 10 wt. % zinc.
 14. The cast product of claim 10,wherein the aluminum alloy strip comprises 1 wt. % to 2.5 wt. % copper.15. The cast product of claim 10, wherein the aluminum alloy stripcomprises 1 wt. % to 2.0 wt. % copper.
 16. The cast product of claim 10,wherein the aluminum alloy strip comprises 1 wt. % to 1.5 wt. % copper.17. The cast product of claim 10, wherein the aluminum alloy stripcomprises 1 wt. % to 2.5 wt. % magnesium.
 18. The cast product of claim10, wherein the aluminum alloy strip comprises 1 wt. % to 2.0 wt. %magnesium.
 19. The cast product of claim 10, wherein the aluminum alloystrip comprises 1 wt. % to 1.5 wt. % magnesium.
 20. A cast productcomprising: an aluminum alloy strip; wherein the aluminum alloy stripcomprises: (i) 4 wt. % to 28 wt. % zinc; and (ii) 1 wt. % to 3 wt. %copper; wherein a variation of a weight percent of the zinc is 15% orless between a surface and a thickness center of the aluminum alloystrip.